The microwave imaging is explored as an imaging modality for early detection of breast cancer. When exposed to electromagnetic waves, the breast tumor has electrical properties that are substantially different from those of healthy breast tissue. This article describes a study for the detection of breast cancer. We examine the ability to detect tumors by a microstrip patch antenna operating at a frequency of 2.45GHz. Using a simple model in the form of a cone. This model consists of the breast skin and fat and the tumor tissues. The study is done according to several distances between the patch antenna and the model of the breast. Simulation results are presented, namely, reflection coefficient, VSWR and radiation pattern of the antenna patch and the current density in the breast skin, fatty tissue and the tumor and also the distribution of magnetic field to give us a clear insight into the concept studied.